1. Field of the Invention
The present invention relates to a calculator and, more particularly, to a calculator capable of recovering cleared values.
2. Description of Related Art
Calculators have been widely used in a variety of fields in our daily lives due to their powerful functions. For example, calculators are used in shopping, accounting, mathematics, engineering, and statistics for providing simple functions such as arithmetic calculations or complicated functions such as scientific operations. When using a calculator, it is possible that a user may enter erroneous data. When such an error is found, the user may press one of a plurality of keys provided by the calculator to correct the error. For example, the user may press a backspace (BACK) key to sequentially correct typing mistakes, a clear entry (CE) key to clear the current data entry, or a clear (C) key to clear the data entry. Furthermore, before the calculator generates the final result, a number of intermediate results may be created, which have to be recorded and/or cleared by pressing CE, C, memory clear (MC) or memory recall clear (MRC) key, so as to perform subsequent operations.
However, when a user operates a calculator and inadvertently presses BACK, CE, C, MC, or MRC key to clear useful data, the typical calculator can only clear or modify the last entered data, while being unable to recover the cleared value. As a result, the user has to perform the whole calculation again. This is quite time-consuming and inconvenient. Therefore, it is desirable for the above conventional calculator to be improved so as to mitigate and/or obviate the aforementioned problems.